David Girard over at Ars Technica:
It’s truly impressive that Photoshop CS5 is successful at adding a lot of useful, engineering-heavy features in CS5, all while porting over to a new and stable Cocoa 64-bit code-base on OS X. And it’s encouraging to see that a program that has no real competitors isn’t just being phoned in. Against the on-going daytime drama of “Apple vs. Flash,” Photoshop is still just a great program and CS5 is a worthwhile update for a broad cross-section of users. My complaints are about minor issues—things like the low-res preview in HDR Merge Pro or window layering with AIR filters—can be addressed in a x.1 update without really slowing people down in the meantime. Nine thumbs up.
I think Girard just nailed the biggest feature: Cocoa.